Cracking the Coding Interview Question 1.4

Question1.4.c

//
//  main.c
//  Question1.4
//
//  Created by JAE SEUNG KOO on 6/24/15.
//  Copyright (c) 2015 JAE SEUNG KOO. All rights reserved.
//

#include <stdio.h>
#define LENGTH 18
char * replaceStr(char *str, int strlen);

int main(int argc, const char * argv[]) {
    char str[LENGTH] = "Mr John Smith    ";
    printf("Output : %s\n", replaceStr(str, strlen(str)));
    return 0;
}

char * replaceStr(char *str, int strlen){
    int str_pos = 0;
    int lastchr = strlen-1;
    for(str_pos = lastchr; str[str_pos] <= 32; str_pos--);
    
    for(int current_chr = str_pos; current_chr > 0; current_chr--, lastchr--){
        str[lastchr] = str[current_chr];
        if(str[current_chr] == 32){
            str[lastchr] = '0';
            str[--lastchr] = '2';
            str[--lastchr] = '%';
        }
    }
    return str;
}